The explosion of wireless digital communication networks and equipment has created a need for compressing more information into a finite spectrum. There is also a need for greater security in communications for both military and commercial applications. As a result, system architecture designers have been prompted to develop wireless communication systems that have increasingly complex modulation, timing, and encryption schemes. Throughout the communication system development process, it is necessary to test system performance by measuring the reliability of transmission and reception of information in the presence of multiple transceivers, in different locations, at different power levels, in the presence of unwanted interferers, reflecting obstacles, and under a variety of environmental conditions. A rapidly operating and sophisticated test apparatus is needed to optimize a transmission system under development and to perform a preliminary qualification of the system prior to expensive and time-consuming field trials.
Prior art test systems for rapid testing between two or more transceivers have included system emulators. A system emulator produces an output that is based upon a pre-programmed emulator response, an input signal, and selected emulator setting (e.g., distance, environment, other transceivers, etc.). Unfortunately, system emulators require information about the system under test in order to produce an accurate output. This requirement presents several problems. First, a new system emulator may need to be designed for each new modulation scheme type for the transmission system under test (SUT). Secondly, a system emulator may introduce errors that produce false positives or negatives in the performance of the SUT. Finally, a system emulator may not replicate a communication environment accurately as a result of interactions between multiple signals at different distances and power levels, thereby resulting in erroneous emulator output(s).
Accordingly, what would be desirable, but has not yet been provided, is an apparatus for simulating RF signal propagation characteristics in a wireless communication network that overcomes the deficiencies of prior art system emulators.